Fuel injection unit



NW, 7, 19330 H. a. A. BURNER FUEL INJECTION UNIT Filed May 22, 1929Patented Nov. 7, 1933 UNITED STATES PATENT OFFICE by mesne ents,to'Packard ompany, Michigan Motor Car Detroit, 'Mich, a corporation ofApplication my 22, 1929. Serial No. 365,094

ZGlaims.

. The invention relates to internal combustion engines of that typegenerally designated as Diesel and in which the fuel is injected at highpressure into a body of compressed air in the combustion chamber. It isthe object of the invention to obtain a construction of fuel in-.iection unit which as such is attachable to the cylinder of the engineand which comprises the nozzle, a pump and a fuel supply connection. Itis a further object to obtain a construction of unit so organized as toobtain uniformity in operation with accurate control of the quantity offuel injected, even where this is exceedingly minute. Still further, itis an object to obtain a construction adapted for commercial manufactureand composed of comparatively few elements of simple construction. Withthese and other advantages in view, the invention consists in theconstruction as hereinafter set forth.

In the drawing:

Figure 1 is a section through a portion of the engine cylinder showingmy improved fuel injection unit applied thereto and in longitudinalsection;

of Figure 1;

Figures 3 and 4 are transverse sections respectively on lines 33 and 4 4of Figure 1.

In the operation of internal combustion engines of the type abovereferred to and particularly in connection with cylinders havingrelatively small piston displacement and designed for high speedengines, it is of the utmost importance first to accurately control thequantity of fuel injected; second, to inject the fuel in a finelydivided form orspray; third, to prevent clogging or stoppage in the fuelline, and fourth, to provide for a relatively large range of variationin the quantity of fuel used for correspondingly carrying the power andspeed of the engine. My improved fuel injection unit is adapted tofulfill these conditions, first, by a nozzle construction adapted tofinely :spray injected fuel while avoiding all danger of clogging;second, in rigidly connecting of discharge, the fuel injection andmeasuring pump; third, in supplying this pump with fuel which has beenfreed as far as possible from all clogging impurities as well as fromair or gas bubbles. The specific construction of some of these elementshas formed the subject matter of other patents taken out by me,including Nos. 1,690,893 of November 6, 1928 and 1,628,657 of May 17,1928. The present invention, however, relates to the novel combinationand organization Figure 2 is a sectional plan view on line 2-2 to thisnozzlev and as close as possible to the point of these and otherelements as hereinafter described.

Asspecifically shown, A is a rigid casing member adapted to be rigidlysecured to the engine cylinder by suitable means such as the laterally00 extending flanges B and the bolts C for clamping said member to a lugor bearing D on the cylinder. The casing A is boredon an axisperpendicular to the cylinder axis and is counterbored and threaded atits inner end to receive v the nozzle member E projecting through anaperture in the lug D to the interior of the cylinder. I The outer endof the casing A is also counterbored and threaded to receive a threadedplug or bushing F which in turn is bored and threaded to receive anadjustable threaded rod or stop member G. The plug F is fashioned at itsinner end to form a, packing fiange surrounding a smooth inwardlyprojecting shank G of the member G.

The nozzle E is provided at its inner end with a flaring conical mouthportion E within which is arranged a knife edge yieldable sprayer valveH formed at the end of a shank H extending through the nozzle and intovthe bore within the member A. The inner end of the shank H is threadedto receive a collar I forming an abutment for one end of a spring Jwhich'is sleeved about said shank, the opposite ends of said springabutting against a bearing on the nozzle E. A cap nut K engaging thethreaded end of the shank H serves to lock the collar I and also forms abearing for abutting against the stop member G, the arrangementbeingsuch that by adjustment of the collar I and cap nut K the spring J maybe 90 properly tensioned and by adjustment of the stop member G theknife edge H may be arranged in very close proximity to the conicalportion E of the nozzle but without actually contacting the same. Theangle of the conical nozzle portion E is greater than the angle of theconical portion forming the knife edge H so that these two surfaces arenon-parallel and the closest point of proximity is at the knife edge.Thus the liquid fuelwhich is ejected from the nozzle must pass 100between the knife edge and the conical surface E' which parts are heldtogether by the relatively heavy pressure of. the spring J If, however,the pressure of the liquid fuel is sufiicientand its speed of ejectiontoo fastto pass through this restricted space, the spring J will yield,permitting a wider separation.

Projecting laterally from the casing member A is an integral threadednipple A through which a tubular casing L may be rigidly attached ,9

to said member A. The member L contains the pump cylinder or barrel Mwhich is inserted therein from the end engaging the nipple and which hasa head M engaging a shoulder within the tubular casing. The pump barrelM at its head end is counter-bored to form a conical seat M for a ballcheck valve N controlling the outlet of the liquid fuel from the barrel.For greater certainty in action I preferably provide a double checkvalve and to this end there is inserted within the tubular casing L andbetween the head M and the nipple A a bushing 0 having a conical seat 0for a second ball check valve N. Springs P and P are arranged toyieldably hold the check valves N and N normally to their respectiveseats, said springs abutting respectively on the shoulder 0 within thebushing O and a shoulder within the nipple A. A fluid passageway Aextends through the nipple to the bore in the member A, thusestablishing communication between the pump barrel and the nozzle.

As shown in Figures 1 and 3, the portion of the tubular casing Lsurrounding the upper portion of the barrel M is formed externally withconical seats Q, Q separated by an annular recess Q These seats areadapted to receive corresponding conical bearings on an annular member Rwhich may be sleeved upon the member L and clamped to its seat by a nutS. Thus there is formed between members L and R an annular channelsurrounding the barrel M and communicating therewith through registeringports L M The annular member R has an annular recess between theportions engaging the bearings Q Q within which is arranged an annularscreen T. The screen T is of a diameter somewhat greater than that ofthe conical bearing Q so as to permit of being sleeved over said bearingwith the member R. There are also gaskets T T at opposite ends of thescreen which bear against the member R and form a sealing contacttherewith leaving an annular space '1 therebetween. On one side of themember R is a transversely extending open ended channel R intersectingthe annular space T so as to be in free communication therewith. Atopposite ends of the channel R are hollow fittings U which are clampedto the member R by a central rod V threaded at its opposite end toengage clamping nuts V. Gaskets U are arranged to seal between thefitting U and the member R and also between said fittings and clampingnuts V. The fittings U are connected to conduits W which lead from thesource of supply for the liquid fuel and also between diflerentcylinders of a multi-cylinder unit. Thus the fuel which is supplied byalow pressure pump (not shown) will pass through the channels R of eachfuel injection unit of a multi-cylinder engine, while the fuel used byeach unit will enter by way of the annular passage 1' through the screenT and annular recess in the member R and then through the ports L M intothe pump barrel. This will avoid carrying clogging impurities which maybe in suspension in the liqud fuel into each unit and in the same mannerwill avoid the forcing of air bubbles with the fuel into the highpressure pump barrel.

Within the pump barrel M is the pump plunger X which is attached at itsouter end to a head X slidable within the casing L and actuated bysuitable mechanism such as a tappet X. A spring Y sleeved around thebarrel M and between the same and the casing L abuts at one end againsta shoulder in the member L thereby forming a means for returning theplunger in the barrel.

With the construction as above described in operation the actuation ofthe tappet X will move the plunger X inwardly in the barrel M and as theend of said plunger passes the ports W will force the fiuid within thebarrel past the check valves N and N and through the passage A into thecasing A from which it will be expelled through the restricted spacebetween the annular knife edge H and the flaring nozzle E. Assuming thatall of the space between the barrel and the discharge end of the nozzlehas once been completely filled with the liquid fuel, it is evident thatthe quantity of liquid discharged from the nozzle will correspondexactly to the displacement of the plunger after the ports M are closed.This is primarily due to the fact that the structure between the nozzleand the plunger is rigid and of such strength that the high hydraulicpressure on the liquid cannot produce any distortion. Also the presenceof the double check valves N N' insures the cutting off of communicationbetween the nozzle and the pump barrel prior to the retraction of theplunger. As before stated, the supply of fuel to the several cylindersis by way of the lateral channels R in each succeeding unit and thistends to carry away any air bubbles or other in suspension instead offorcing them into the pump barrel.

What I claim as my invention is:

1. A rigid fuel injection unit for an internal combustion enginecomprising a rigid casing member carrying a nozzle, means for imposing ahigh resistance to the passage of fuel throughv said nozzle, a secondrigid casing member can!- ing a ported pump barrel and a plungerreciprocable past the port, a bushing in the second casing, one-wayvalve means located in the end of the bushing nearest the first casingmember and closing against said bushing, a second oneway valve locatedin the end of the pump barrel and closing thereagainst, said firstmentioned 120 casing member being rigidly secured to but detachable fromsaid second mentioned casin member and firmly clamping the bushingagainst the barrel, said bushing and first mentioned casing membertogether forming an inextensible passageway for the fuel from saidbarrel to said nozzle.

2. A rigid fuel injection unit foran internal combustion enginecomprising a rigid casing member carrying a nozzle, means for imposing am high resistance to the passage of fuel through said nozzle, 9. secondrigid casing member carrying a ported .pump barrel and a plungerreciprocable past the port, a bushing in the second casing, one-wayvalve means located in the end of the bushing nearest the first casingmember and closing against said bushing, a second one way valve locatedin the end of the pump barrel and closing thereagainst, said firstmentioned casing member being rigidly secured to but detachable fromsaid second mentioned casing member and firmly clamping the bushingagainst the barrel, said bushing and'first mentioned casing membertogether forming an inextensible passageway for the fuel from saidbarrel to said 145 nozzle, and said passageway having relatively shortlength and relatively small cross section.

impurities held 105

